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| 5/24 |
| 2001/5/29-30 [Computer/HW/Drives] UID:21387 Activity:insanely high |
5/29 To followup on my previous thread on CD-Rs. I tried four different
machines: 1 sun u5, 2 laptops, and 1 PC and I still cannot read the
corrupted CD-R. I'm screwed. So are CD-RWs any better? They're
more expensive hence "better"?
\_ No, they are worse for archiving. --dim
\_ What brand was the CD-R? (Just curious.)
\_ I used TDK. Anybody recommend a brand that they've had
no problems with?
\_ Mitsui gold-on-gold. It's not the brand, but the dye
used. All dyes except phthalocyanine are unstable. So-called
"platinum" discs usually use phthalocyanine, as do many
gold discs. Do not use green (cyanine), blue (azu), or another
color (hybrid) no matter whose name is on it. --dim
\_ wow, that's one of the most useful pieces of technical
information i've seen on the motd in a while. cool.
\_ depends who you listen to. if you listen to mitsui,
who has a patent for phthalocyanine, they're going to
say phthalocyanine is the best. if you listen to verbatim,
who have a patent on metal azo, they'll say theirs is
the best. http://www.verbatim.com.au/Media/93707.html
the moral is to not do stupid things like leave cd's
in direct sunlight etc. no matter what kind it is.
\_ Gold costs more to manufacture and has a better
shelf life in spite of the fact that silver does
have higher reflectivity. Most unbiased sources of
information do in fact tout phthalocyanine dye as
the best. Personal experience with it is also very
good. If you read the claim on the URL you produced
you will see that they claim superiority based on
"lightfastness". That is an advantage, but not the
whole story. Dyes other than phthalocyanine "move"
during the burning process. In short, there are
advantages to each dye but for archival (stored in
the dark in a controlled environment) you want
phthalocyanine dye and a gold reflective layer. --dim
\_ hmm, I'd be quite interested in seeing one of these
unbiased sources for myself. in my travels such
things have been rare.
\_ Do a search on the web. --dim
\_ Do a search on the web. Sandia Labs did a
test. MIT Library decided to go with gold
phthalocyanine disks (Kodak). JPL is using
the Mitsui disks I mentioned earlier based on
experience. Here's another study which touts
phthalocyanine disks:
http://ikrweb.uni-muenster.de/aptdir/aktuelles/arc
hivmedien.html . Believe what you will. --dim
hivmedien.html says "After aging, two media
types were completely unreadable--Taiyo Yuden
and TDK. These manufacturers use a cyanine
dye, which is less stable tha[n] the
phthalocyanine dye used by other manufacturers."
Believe what you will. You know best. --dim
\_ Andy McFadden's CD-R FAQ has a section on media:
http://www.cdrfaq.org/faq07.html#S7 -tom
\_ Well, I've had no problems with anything except those "gold"
noname ones. One of those with my personal files on it
stopped being readable one day. But the weird thing was,
I kept it anyway, and months later tried it and it worked.
I've had good results with Imation and Kingston (phthalocy.)
but recently have been using Verbatim (blue azo) without
problems; azo is claimed to be as good as the gold/platinum
etc. but time will tell. Regardless, another possible issue
is: Did you write on the disc, and if so, using what?
\_ http://www.cdmediaworld.com/hardware/cdrom/cd_dye.shtml
the entire site has tons of info |
| 5/24 |
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| www.verbatim.com.au/Media/93707.html The page cannot be found The page you are looking for might have been removed, had its name changed, or is temporarily unavailable. Please try the following: * If you typed the page address in the Address bar, make sure that it is spelled correctly. |
| ikrweb.uni-muenster.de/aptdir/aktuelles/arc Not Found The requested URL /aptdir/aktuelles/arc was not found on this server. |
| www.cdrfaq.org/faq07.html#S7 Media (1998/04/06) This section covers recordable CD media. The dye types currently in use are: * cyanine dye, which is cyan blue in color (hence the name); In addition, Kodak has patented a "formazan" dye, which is light green. This has been reported to be a hybrid of cyanine and phthalocyanine. The reflective layer is either a silver alloy, the exact composition of which is proprietary, or 24K gold. Aluminum isn't used in CD-R media because the metal reacts with the dyes. The color you see is determined by the color of the reflective layer (gold or silver) and the color of the dye (light blue, dark blue, green, or colorless). For example, combining a gold reflective layer with cyanine (blue) dye results in a disc that is gold on the label side and green on the writing side. Many people have jumped to the conclusion that "silver" discs are made with pure silver, and have attempted to speculate on the relative reflectivity and lifespan of the media based on that assumption. According to one source, silver is susceptible to corrosion when exposed to sulfur dioxide (a common air pollutant), so manufacturers use alloys of silver to inhibit corrosion. Taiyo Yuden produced the original gold/green CDs, which were used during the development of CD-R standards. Mitsui Toatsu Chemicals invented the process for gold/gold CDs. Mitsubishi's NCC subsidiary developed the metalized azo dye. Silver/blue CD-Rs, manufactured with a process patented by Verbatim, first became widely available in 1996. According to the Ricoh web site, the silver/silver "Platinum" discs, based on "advanced phthalocyanine dye", were introduced by them in 1997. They didn't really appear on the market until mid-1998 though. One reason why there are multiple formulations is that the materials and processes for each are patented. If a new vendor wants to get into the CD-R market, they have to come up with a new combination of materials that conforms to the Orange Book specifications. Kodak's "Infoguard") that makes the CD more scratch-resistant, but doesn't affect the way information is stored. The top (label) side of the CD is the part to be most concerned about, since that's where the data lives, and it's easy to damage on a CD-R. Applying a full circular CD label will help prevent scratches. The data side (opposite the label side) is a dark silvery gray that is difficult to describe. What's the typical BLER (BLock Error Rate) for the media? Some audio CD players (like the ones you'd find in a car stereo) have worked successfully with one brand of media but not another. There's no "best" kind, other than what works the best for you. Some people have found brand X CD-R units work well with media type Y, while other people with the same unit have had different results. Recording a disc at 4x may make it unreadable on some drives, even though a disc recorded at 2x on the same drive works fine. To top it all off, someone observed that discs burned with one brand of CD-R weren't readable in cheap CD-ROM drives, even though the same kind of media burned in a different device worked fine. The performance of any piece of media is always a combination of the disc, the drive that recorded it, and the drive that reads it. A number of specific discoveries have been posted to Usenet, but none of them are conclusive. Many people have reported that Kenwood CD players don't deal with CD-Rs very well, while Alpine units play nearly everything. However, things change as product lines evolve over time. Some users have found that the *quality* of audio recordings can vary depending on the media. Whatever the case, if you find that CD-Rs don't sound as good as the originals, it's worthwhile to try a different kind of media or a different player. One final comment: while there are clearly defined standards for CD-R media, there are no such standards for CD and CD-ROM drives -- other than that they be able to read CDs. It is possible for media to be within allowed tolerances, but be unreadable by a CD-ROM drive that can handle pressed discs without trouble. All you can do in this sort of situation is find a better-quality CD or CD-ROM drive, or switch to a brand of media whose characteristics are on the other side of the tolerance zone. They are now manufactured by TDK, Ricoh, Kodak, and probably several others as well. Mitsui Toatsu Chemicals (MTC) made the first "gold" CDs. They are now manufactured by Kodak and possibly others as well. Yamaha and Sony) are actually made by a handful of major disc manufacturers. Attempting to keep track of who makes what is a difficult proposition at best, since new manufacturing plants are being built, and resellers can switch vendors. See 35 section (2-33) for notes about identifying the source of a CD-R. You can't tell how well a disc will work just by looking at it; Statements to the effect that "dark green" is better than "light green" are absurd. Some discs are more translucent than others, but that doesn't matter: they only have to reflect light in the 780nm wavelength, not the entire visible spectrum. It's probably a good idea to start by selecting media that is certified for your recorder's desired write speed. See 37 section (3-31) for some other remarks about recording speed. Speed considerations are more important for CD-RW than CD-R. Many drives refuse to record at speeds higher than the disc is rated for. On top of that, there are "ultra speed +" blanks (for 32x recording), "ultra speed" blanks (for 8x-24x), "high speed" blanks (for 4x-10x) and "standard" blanks (for 1x-4x). The faster blanks are labeled with a "High Speed CD-RW" or "Ultra Speed CD-RW" logo, and will not work in older drives. The Orange Book standard was written based on the original "green" cyanine discs from Taiyo Yuden. Cyanine dye is more forgiving of marginal read/write power variations than "gold" phthalocyanine dye, making them easier to read on some drives. On the other hand, phthalocyanine is less sensitive to sunlight and UV radiation, suggesting that they would last longer under adverse conditions. Manufacturers of phthalocyanine-based media claim it has a longer lifespan and will work better in higher speed recording than cyanine discs. There is no advantage to using expensive "audio CD-Rs" or "music blanks". There is no difference in quality between consumer audio blanks and standard blanks from a given manufacturer. If you have a consumer audio CD recorder, you simply have no other choice. There is no way to "convert" a standard blank into a consumer audio blank. See 39 section (5-12) for notes on how you can trick certain recorders into accepting standard blanks. Trying samples of blanks is strongly recommended before you make a major purchase. Remember to try them in your reader as well as your writer; Maxell's CD-R media earned a miserable reputation on Usenet. In April '97 Maxell announced reformulated media that seemed to work better than the previous ones. However, some brands are recommended more often than others. Brands most often recommended: Mitsui, Kodak, Taiyo Yuden, and TDK. It appears that HP, Philips, Sony, Yamaha, and Fuji use these manufacturers for most of their disks. Sometimes a particular line of discs from a particular manufacturer or reseller will be better than others from the same company. For example, Verbatim DataLifePlus discs are recognized as pretty good, but Verbatim ValuLife are seen as being of much lower quality. For example, in June 2003 Mitsui Advanced Media was purchased from Mitsui Chemicals by Computer Support Italcard (CSI) of Italy to form MAM-A, Inc. Some manufacturers maintain plants in different countries, and don't always maintain the same level of quality. In humid tropical climates, care must be taken to find discs that stand up to the weather. Mitsubishi CD-R 700 and Melody 80 Platinum discs fared much better. In general, CD-RW media isn't recommended for long-term backups or archives of valuable data. The manufacturers claim 75 years (cyanine dye, used in "green" discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years ("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has be... |
| www.cdmediaworld.com/hardware/cdrom/cd_dye.shtml Here is an overview of all available Dye materials, all organic based: Dye Material Patent Holder Dye Color Cyanine Taiyo Yuden Blue PhthaloCyanine Mitsui Toatsu Chemicals Transparent Metallized Azo Verbatim/Mitsubishi Blue Advanced PhthaloCyanine Mitsui Toatsu Chemicals Transparent Formazan Kodak Japan Limited Light Green The Formazan Dye is a hybrid Cyanine/PhthaloCyanine combination which has been developed by Kodak. In addition, the polycarbonate substrate is etched with a spiral pre-groove. This pre-groove is used for guiding the laser beam, time measurement and various controls during recording. The laser beam, modulated by the recording signal, is focused on the groove. The beam heats and melts the recording layer of organic dye on the polycarbonate substrate, forming a series of pits. This pits are physically extremely stable, and are ideal for long-term data storage with the highest degree of reliability. Fuji Photo Film Co, Ltd Gigastorage Corporation Lead Data Inc. Mitsubishi Chemicals Corporation Multi Media Masters & Machinary SA Pioneer Video Corporation Taiyo Yuden Company Limited 2 Cyanine Blue Mitsubishi Chemicals Corporation Multi Media Masters & Machinary SA 3 Cyanine Green Blue King Pro Mediatek Inc. All other CD-R manufacturers have their CD-R's made by the above companies or they license the patent to be able to make CD-R's. The color of the CD-R disc is related to the color of the specific dye that was used in the recording layer. This base dye color is modified when the reflective coating (gold or silver) is added. Some of the dye-reflective coating combinations appear green, some appear blue and others appear yellow/gold. Visual differences between various media types are irrelevant from the standpoint of their actual operation. At 780 nm, where CD-R recorders and CD-ROM readers function, the media are, for all intents and purposes, indistinguishable from an optical recording standpoint. The gold-colored CD-R uses the PhthaloCyanine pigment and a gold reflection layer. As the pigment is transparent, the golden reflection layer shines through the bottom side giving the golden' look. Compared to the other colored media, the reflection contrast of the golden medium is the highest and the durability of such CD-R's is said to be over 100 years. As the golden medium's reflective property is the highest, if your friends or customers have problems reading data from any other burnt media, try using the gold medium CD-R. The green CD-R, the cheapest of the three, uses the Cyanine pigment. By itself, the pigment is blue in color, but together with the gold reflective layer, the bottom appears green. However, cyanine's ability to maintain reflectivity is poor giving it a life span of about 10 years. It also delivers the weakest reflection contrasts and thus can cause read errors when run on old CD-ROM drives. Lately cyanine formula has been altered which results in a much higher life span (20 to 50 years). The gold reflection layer has also been replaced by a silver reflection layer this make the color of the bottom appear blue. Like cyanine, it is blue in color but unlike the green CD-R it uses a silver reflection layer which gives the blue color. Manufacturers claim blue CD-R's are as durable as golden ones. |